Transmit-receive device



Aug. 9, 1949.

B. B. CORK ET AL 45 TRANSMIT RECEIVE DEVICE Filed May 25, 1945 FIGURE 2 INVENTORS BRUCE B. CORK Y GEORGE R. BREWER W,Lm ILLAZ/Q ATTORNEY Patented Aug. 9, 1949 TRAN SMIT-RECEIVE DEVICE Bruce B. Cork, Cambridge, and George R. Brewer,

Brookline, Mass, assignors, by mesne assignments, to the United States of America as represented by the Secretary of War Application May 23, 1945, Serial No. 595,358

2 Claims. (Cl. 17844) This invention relates to a transmit-receive device.

In the copending application of Bruce B. Cork and James L. Lawson, Serial No. 591,588, filed May 2, 1945, a protective discharge or T-R (Transmit-receive) device is disclosed in which electrical energy is coupled into a resonant cavity from a radio-frequency transmission means through an opening in the wall of the resonator. A glass seal is provided to seal the opening so that the pressure in the interior of the resonant cavity may be controlled. In making the glassto-metal seal. dielectric is introduced in the path of the electrostatic lines of force within the cavity. The design of the seal disclosed in the abovementioned application is such that the electrostatic lines from the center post tend to converge on the glass. Because of the above factors, some difficulty has been experienced in obtaining an effective Q of the resonant cavity which is sufliciently high for certain contemplated uses of the device. Q is defined as the ratio of the energy stored in the cavity to the energy dissipated in the cavity per half-cycle of the electric energy.

It is an object of the present invention to improve the seal ior a T-R device so that the Q of the resonant cavity is increased.

The invention in general consists of a cavityresonator having an opening in its wall, the metal around the opening being reduced in thickness so as to reduce the thickness of the seal. The opening in the wall of the resonator is made somewhat smaller than the center post of the T-R device, so that the electrostatic lines of force may converge on the metal.

For a better understanding of the invention, together with other and further objects thereof, reference is made to the following description, taken in connection with the accompanying drawings, in which:

Fig. 1 is a sectional view of a transmit-receive device embodying my invention; and

Fig. 2 is an expanded view of the portion of Fig. 1 in the region of the seal.

touching a second wall H of the cavity-resonator ID. A circular ring of metal I6 is inserted in an opening in wall l4, and the opening in ring I6 is closed b a glass seal H. An opening I8 is formed in wave-guide II, and is coincident with the opening in ring l6.

Referring now to Fig. 2, there is shown, on an enlarged scale, the ring I 6, the glass seal IT, a portion of wall l4, and a portion of center post l2.

The paths of the electrostatic lines of force extending from center post l2 in the direction of wall l4, are represented by lines numbered 20.

Ring I6 is made of a metal having substantially the same coefficient of expansion as glass. An airtight seal is made between ring I 6 and wall It. This seal is of such a nature that good electrical contact is made between ring l6 and wall I! at all points where they fit together. Ring I6 is made thinner toward the center, whereby the thickness of the glass seal H, where it joins ring I6, is reduced to a minimum. The diameter of the opening in ring I6 is less than the diameter of center post l2 so the lines of force 20 from center post l2 will terminate on ring I6 or wall I, rather than on glass seal l1. Since Referring now more particularly to Fig. 1, there the glass seal I! is now almost completely removed from the path of the electric lines of force within the cavity-resonator Hi, the dielectric losses that would occur in the glass are reduced to a minimum. The reduced thickness of seal l1 also minimizes the dielectric loss that occurs when ener y passes from wave-guide I I into cavity resonator l0.

While there has been described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention.

What is claimed is:

1. A transmit-receive device comprising a cavity-resonator formed with a center post extending from a first wall thereof to the vicinity of a second wall of the same, said second wall being formed with an opening therein coaxially located with respect to said center post, means for sealing said opening in said resonator comprising a metallic ring joined to said second wall, said ring having a central opening smaller in cross-secbut not tional area than the cross-sectional area of said center post, and a glass seal for closing said opening in said ring, the junction of said ring and said seal being so formed that the thickness of said seal is reduced substantially to a minimum.

2. A transmit-receive device comprising a cavity-resonator formed with a center post extending from a first wall thereof to the vicinity of a second wall of the same, said second wall being formed with an opening therein coaxially located with respect to said center post, means for seal- 10 ing said openin in said resonator comprising a metallic ring 'jo'meditosaid second-wallgsaid ring having a central opening smaller in cross-sec- 4 tional area than the cross-sectional area of said center post, and a seal of glass-like material closing said opening in said ring.

BRUCE B. CORK. GEORGE R. BREWER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date iNt'imber Chevign'y June 20, 1944 

